1. Field of the Invention
The present invention relates to lens caps, and especially to an integrally formed lens cap for a semiconductor laser package.
2. Related Art
Since the development of laser diodes, many applications for their use have been developed. Increasingly, laser diodes are employed for communications and are integral to optical disc recording and storage systems. However, laser diodes are fragile, and undue mechanical impact and humidity can affect their performance. To protect them from damage, laser packages are designed.
A conventional semiconductor laser package includes a base and a cap engaging the base to protect laser diodes fixed on the base. The package is generally in the shape of a xe2x80x9ccanxe2x80x9d and is made of a metal material with an opening in a top and an optical glass element attached to cover the opening and permitting passage of laser emissions therethrough.
A conventional semiconductor laser package is disclosed in the U.S. Pat. No. 5,052,009, as shown in FIG. 7. The laser device 10 includes a base 11 and a housing 13 engaging with the base 11 to accommodate laser diodes 14, 15 therebetween. The laser diodes 14, 15 are fixed on the base. A glass plate 16 is attached to an opening in the housing 13 by adhesive resin to form a window 12 in a top portion of the housing 13. However, extra procedures are needed to apply and cure the adhesive resin, and to optimize the glass plate, which is very troublesome and costly in labor. In addition, the adhesive resin is subject to flux during the manufacture, which can lead to contamination of the glass plate and can affect the transparency of the glass plate. Moreover, the adhesive resin is susceptible to degradation, when the window is subjected to mechanical impact or high temperature, which is adverse to the adhesion between the glass plate and the housing.
Accordingly, a low cost semiconductor laser package that is easy to manufacture on a large scale is desired. The copending applications of Ser. Nos. 10/142,448 filed on May 9, 2002 and 10/152,409 filed on May 20, 2002, with the same inventor and the same assignee as the present invention, disclose some approaches.
An object of the present invention is to provide a low cost lens cap for a semiconductor laser package that is easy to manufacture on a large scale.
Another object of the present invention is to provide a lens cap for a semiconductor laser package having a strong structure.
To achieve the above-mentioned objects, a lens cap for a semiconductor laser package in accordance with a preferred embodiment of the present invention comprises an optical element made of a plastic material and a housing. The housing includes a top portion, a sidewall and a flange. An opening is provided in the top portion. The optical element is insert molded into the housing.
Other objects, advantages and novel features of the present invention will be drawn from the following detailed description of preferred embodiments of the present invention.